Solar/Fridge Question

[MCW]

Hi, new member here. Sorry, let me try this again minus my errors. I recently picked up a new 2017 Hawk (love it!) w/ the Dometic (RM2191/93), 3-way fridge.

I am confused about running the fridge off of solar. I was told I would need to run it off of shore power, or propane, or install an inverter to make it work with my factory solar setup.

I understand it draws a lot of power but is it possible to run this off of solar (at least while driving), as-is from the factory, or do I need to install an inverter?

Do people drive with their refrigerators running off propane?

Thanks

 

[longhorn1]

First you mention running your 2-way fridge on propane or plugged in. The 2-way fridge (compressor fridge) works off 110 (when plugged in) or off 12 volt. The 3-way fridge works of propane, 12 volt, or 110 shore power. Can you clarify which type you have? When you are camping without shore power your compressor fridge is working off 12 volt. Your solar panel is charging the batteries, or driving your truck is charging the batteries. You didn't mention the build year and whether this is bought new or used. If this is brand new it doesn't sound like the dealer went over everything thoroughly.

 

[ardvark]

May just have a two-way with propane and 120 VAC.

 

[MCW]

Sorry. The 2-way was marked on my invoice, but it's a 3-way. It was pretty late by the time my install was complete and I did not get a lot of detail on the systems. Dealer was great, we just both had to take off so I neglected to ask about certain details.

 

[PaulT]

Your fridge pulls 10 amps on DC power. With the factory 2 AGM battery set up, you have 150 amp hours total or 75 amp hours available if pulling down to the recommended 50% maximum drawdown. At 10 amps, that allows 7.5 hours of run time on batteries. Consider how much solar power watts you would need to recharge the batteries on a daily basis with the available solar where and when you camp.

https://www.dometic.com/en-us/us/products/food-and-beverage/refrigeration/refrigerators/dometic-compact-refrigerator30914#specifications

Running on DC while driving will work if your alternator to camper wiring allows at least 10 amps to reach the camper batteries. Keep in mind that using an inverter to run off AC will draw down your batteries even faster due to losses in converting the battery power to AC.

Paul
ps. Unless you run the inverter under the hood off the alternator and run the AC back to the camper.

 

[Vic Harder]

Hard to run a 3-way off batteries. They are less efficient than the two ways, which can run off batteries/solar for days (weeks). As Paul says above, the three way pulls 10A, a two way just 2A or so. That's the bad news.

The good news is with a two way, it can be done easily. The inverter you aske about could then easily run most everything in the camper that you might want to charge up. I am currently running just a small inverter (100w) but looking at a 1500W pure sine wave unit at some point. Keep in mind that a big inverter will suck power at an alarming rate, as Paul says above.

FYI, I have 465W of solar, and 225AH of batteries with 2g wire from alternator to batteries.

 

[CougarCouple]

Hello MCW
Yes I have driven with my refrigerator running on propane! It was a class B camper but don't see why it won't work. The 12v selection killed my battery even when driving. The 3way fridges are absorption systems, no compressor. They use heating element to work. This consumes lots of a/c or D.C. power.

Russ

 

[whwv]

I have the same fridge in my 2016 Fleet. I use 12v when driving because the propane blows out on the highway and I also don't have to worry about the flame when I'm fueling up. However, I switch to propane for any stop over an hour.

In my opinion, the 12v is really for driving only since the fridge is very inefficient on electricity. It's so efficient on propane though, that even if I do have 120v I normally don't bother plugging in and just turn on the propane.

On a side note, that fridge likes to open while driving since the door lock is useless. I added a piece of velcro to keep it closed and others have added latches.

 

[ardvark]

You know the flame blowing out when that fridge is used on truck campers has been a problem for decades and at one time Dometic even had a white paper out on it for techs, although I have no idea where mine is. My fridge does blow out on propane only if hit by a hard wind directly from the side. Some days it is not a problem. It is interesting as it is not a problem on other fridges on other types of RVs.

Dometic calls the DC element a sustainer only and not intended to cool the fridge down, just keep it cool as long as it was cooled down first on propane or AC and then only with the door left shut. I use a bungy across my door to keep it closed when underway. Same with me never getting around to fixing the problem.

I am guessing lack of demand and limited profit margin so Dometic just lets those things slide eventhough everyone seems to know about them.

 

[MCW]

Thanks for all of your helpful responses!

 

[craig333]

You guys are familiar with this thread?

http://www.wanderthewest.com/forum/topic/1111-tech-tip-auto-relighter-for-propane-refrigerators/

 

[gaylon]

I have the same fridge and I usually get it super cold on AC at the house before leaving, including putting into it all the food and beverages. I run it on DC while driving with the cold setting set to mid range, but switch it to propane and the coldest setting when stopped for more than gassing up. Pain in the ass, yes a bit. But it is a big fridge that only sips propane in camp to stay super cold and that is worth it to me. For driving, I use a medium igloo cooler in the back of the truck and I freeze cooler blocks in the camper fridge overnight for that cooler if driving everyday or so.

Also, I have a secondary latch to keep the fridge from opening while driving, which is a problem with these fridges if you put any weight in the door.

 

[MCW]

I think that is the way to do it. I normally can't plug in but am impressed by the efficiency of the solar. Thanks again for the helpful responses!